Well, your right, running the oil too cool is bad too and possible if you didn't have a oil thermostat in your front mount oil cooler. But the side housings and rotor housing surface which are effected by the coolant temp the most shouldn't be too cold either or meterial will be removed at a faster rate. This is partically the reasoning behing lapping those side housings because the side seals and oil rings are more abrasive at too cool a tempature or on the other extreme too hot will warp the rotor housings and sideplates and take the springs in there and flatten them.

My '88 has that too.
The only reason for that coolant heating the throttle body on the EFI model is to heat the thermal wax to slowing open the butterflys in the throttle for easy cold starting....it works like a choke on a carb'd car. A popular mod to remove the thermowax and coolant running to it. And ofcourse, remove the restrictor butterflys in there as they can obstruct flow some. The gain in flow is small so its not that great of a mod to do unless you live were the temp is allways high because you have to feather the throttle more while its warming up. But other then that, the intake in NOT heated as there is no hole in the rotor housings for the EFI 6port engines for coolant flow. Also, you have the subzero starting assist that injects a small amount of antifreeze on very cold days also, but is not heated of course.


I wasn't, but EFI 6port engines 84-91 as far as I know all have the same setup(subzero assist, coolant activated thermowax operated butterfly/choke), except the northern cars have a plug-in block heater. I am unaware of a battery heater on any RX-7 though. Do you have one?

 

Yes I do, as does virtually everyone on the Canadian prairies whether dealer installed or aftermarket

 

That would be me, and you're welcome. The thread most definitely deserves it.